Municipal and plumbing and sanitary codes mandate that waste water be delivered automatically to sewer line water traps, and trap primer valves have conventionally been employed to provide a fresh water barrier in the trap of a sewer line to inhibit reverse migration of odors from the sewer line to a dwelling. In that connection, the present invention relates to a trap primer valve assembly of the flow-through type which is provided with a flow regulator operable for automatically metering water to a trap. The present invention is directed to an improved flow-through trap primer valve assembly which incorporates a flow regulator operable for metering liquid from a supply, such as the water main of a building, or residence, apartment, restaurant, etc., to the trap of the building.
The flow regulator operates from an initially closed position to variable open positions actuated from the flow from the main, and includes a check valve utilizing a piston mounted inside a cartridge. The idea is that during even relatively low flow rates, for example in the range of at least about one-half gallon per minute, as when a faucet is turned on, the piston will be raised a predetermined amount, say 3/16 of an inch, to permit flow of water to a jet for dispensing the liquid to an outlet directed to the trap, thereby to replenish the trap with fresh water.
The check valve of the present invention is mounted within a cartridge which in turn is mounted in a housing, which may be constructed in the T-shaped configuration, with inlet and outlet flow-through ports, as well as a port including a jet for dispensing water to the sewer line trap. The check valve includes a piston normally biased downwardly by a spring so that the head of the piston engages and thereby seals the inlet of the jet, so that no water flows into the jet. Upon an increase in demand of water, as when a faucet is actuated, the flow engages the piston to elevate it enabling water not only to pass to the faucet, but also to permit a metered amount of water to be dispensed to the jet and downwardly to the trap.
The piston is mounted for reciprocal movement in a cartridge-like device, which includes elongate sides formed of spaced-apart, upwardly extending elements. This construction facilitates flow of water upwardly from the inlet through the spaces existing between the elements when the water flow pushes the piston upwardly. The pressure exerted by the spring against the piston may be selectively adjusted, depending upon conditions and need, by a primer cap mounted on top of the housing of the trap primer valve assembly. The primer cap can be adjusted to engage a smaller, conical cap which partially houses the spring.
As the primer cap is adjusted upwardly or downwardly, the spring will correspondingly exert more or less pressure on the piston head, thereby requiring more or less water flow to engage the piston head to lift it off and upwardly from its sealed position when it engages the opening of the jet that is directed to the trap. This adjustability feature of the present invention enables “fine tuning” to select the amount of water delivered to the jet, and ultimately, to the sewer line trap. The piston enables this fine tuning because it can readily slide upwardly and downwardly along the inner surface of the upstanding elements of the cartridge and be guided thereby.